Method for manufacturing light guide plates

ABSTRACT

A method for manufacturing a light guide plate, includes: providing a first mold having a first contact surface, a second mold, and a reflector having a reflecting surface, the first mold defining a cavity from the first contact surface toward an inner portion thereof and having a gate communicated with the cavity; sandwiching the reflector between the first and second molds with the reflecting surface tightly contacting with the contact surface to enclose the cavity; injecting molten transparent resin into the cavity through the gate to fill the cavity up with the molten transparent resin, thereby forming a light guide plate body on the reflecting surface of the reflector; cooling the light guide plate body to solidify the light guide plate body in the cavity; and separating the first and second molds.

BACKGROUND

1. Technical Field

The present disclosure relates to a method for manufacturing a light guide plate, and more particularly, a method for manufacturing a light guide plate including a light guide plate body and a reflector formed on a surface of the light guide plate body.

2. Description of Related Art

Liquid crystal display devices usually adopt backlight modules as light source. A backlight module generally includes a light guide plate and a light source. The light source is located beside one end or two opposite ends of the light guide plate, used to emit incident light beams into the light guide plate. The light guide plate is used to lead travel of the incident light beams therein and ensure that most of the incident light beams can be emitted from an emission surface thereof. In this way, linear light sources, such as cold cathode fluorescence lamp (CCFL), or point light sources, such as light emitting diodes, are converted into surface light sources.

The light guide plate generally includes a high transparent plate and a reflector. In a process of manufacturing the light guide plate, a high transparent plate and a reflector are fabricated separately, and then the reflector is attached on at least a surface of the transparent plate except a light incident surface thereof. The process costs much time. It is necessary to provide a method for manufacture a light guide plate to improve industrial efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the method for manufacturing a light guide plate can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the different views.

FIG. 1 is a flow chart of a method for manufacturing a light guide plate.

FIG. 2 is a schematic view showing an injection molding machine and a reflector in accordance with an exemplary embodiment.

FIG. 3 is similar to FIG. 2, but showing the reflector is sandwiched using the injection molding machine.

FIG. 4 is similar to FIG. 3, but showing a light guide plate body is formed on a reflecting surface of the reflector.

FIG. 5 is similar to FIG. 4, but showing a light guide plate is obtained.

DETAILED DESCRIPTION

Referring to FIGS. 1-5, a method for manufacturing a light guide plate provided in an exemplary embodiment includes the following steps in no particular order.

In step 1, as shown in FIGS. 1, 2, a horizontal injection molding machine 10 and a reflector 20 are provided. The injection molding machine 10 includes a hopper 14, a heater 11, an injecting nozzle 13, a first mold 121 and a second mold 122 matched with the first mold 121. The hopper 14 communicates with the heater 11, and is configured for feeding plastic resin particles to the heater 11. The heater 11 generally encompasses a screw rod (not shown) for compressing the resin particles from the hopper 14, melting the resin particles and transporting molten resin to the injecting nozzle 13. The first mold 121 has a first contact surface 1211, and defines a cavity 1210 from the first contact surface 1211 toward an inner portion thereof, and a gate 1222 communicating with the cavity 1210. The second mold 122 has a second contact surface 1212. When the first mold 121 contacts with the second mold 122 in a manner that the first contact surface 1211 contacts the second contact surface 1212, the first mold 121 communicates with the external through the gate 1222. The injecting nozzle 13 is configured for injecting molten resin into the cavity 1210 through the gate 1222.

The reflector 20 includes a base 21 and a reflecting layer 22 formed on a surface of the base 21. The base 21 is made of a material selected from the consisting group of plastic, glass, ceramic, and metal. The reflecting layer 22 is made of silver, having a reflecting surface 221 for reflecting the light emitting from a point light source onto a light output surface of a light guide plate. Alternatively, the reflector 20 contains a typical white reflecting member in an inner portion thereof.

In step 2, as shown in FIGS. 1 and 3, the reflector 20 is sandwiched using the first and second molds 121, 122 in a way that the cavity 1210 is substantially covered with the reflector 20 and the reflecting surface 221 faces the gate 1222. In detail, firstly, the reflector 20 is positioned using a typical mechanical hand (not shown in FIG. 3) with the reflecting surface 221 contacting the first contact surface 1211. Then the second mold 122 moves toward the reflector 20 until the second contact surface 1212 of the second mold 122 contacts the reflector 20.

In step 3, as shown in FIGS. 1, 3 and 4, molten resin is injected into the cavity 1210 through the gate 1222 with filling the cavity 1210, thereby a preformed light guide plate body 30 a is formed on the reflector 20. The molten resin is high transparent, made of polycarbonate (PC) or polyethylene terephthalate (PET).

In step 4, as shown in FIGS. 1, 4 and 5, the preformed light guide plate body 30 a is kept between the first, second mold 121, 122 and cooled with a cooling system (not shown) of the injection molding machine until the light guide plate body 30 a is solidified and has a stable shape under atmosphere temperature. Thereafter, as shown in FIG. 1, in step 5, the second mold 122 is separated from the first mold 121, and the reflector 20 with the light guide plate body 30 a is removed. Therefore, a light guide 50 including the light guide plate body 30 a and the reflector 20 is obtained.

Additionally, the reflector 20 is trimmed to the same shape and size with the light guide plate body 30 a after pulling the light guide 50 out of the injection molding machine 10. In the present embodiment, the light guide plate body 30 a is directly formed on the reflector 20 using injection molding method. Therefore, the process is simplified, and time is saved.

While certain embodiments have been described and exemplified above, various other embodiments will be apparent to those skilled in the art from the foregoing disclosure. The present invention is not limited to the particular embodiments described and exemplified but is capable of considerable variation and modification without departure from the scope of the appended claims. 

1. A method for manufacturing a light guide plate, comprising: providing a first mold having a first contact surface, a second mold, and a reflector having a reflecting surface, the first mold defining a cavity in the first contact surface toward and having a gate communicated with the cavity; sandwiching the reflector between the first and second molds, the reflecting surface tightly contacting the contact surface thus the cavity being covered by the reflector; injecting molten transparent resin into the cavity through the gate to fill the cavity up with the molten transparent resin, thereby forming a light guide plate body on the reflecting surface of the reflector; cooling the light guide plate body to solidify the light guide plate body in the cavity; and separating the first and second molds.
 2. The method of claim 1, further comprising trimming the reflector until the shape such that the size of the reflector is substantially same as that of the light guide plate body. 